import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 25397
 * Date: 2021-11-26
 * Time: 19:134
 *
 */
public class test {
    /*public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        List list=new ArrayList();
        String str=scanner.nextLine();
        for(int i=0;i<str.length();i++){
            if(!list.contains(str.charAt(i))){
                list.add(str.charAt(i));
            }
        }
        for(Object x:list){
            System.out.print(x);
        }
    }*/


    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        while(scanner.hasNext()){
            List list=new ArrayList();
            String str=scanner.nextLine();
            for(int i=0;i<str.length();i++){
                if(!list.contains(str.charAt(i))){
                    list.add(str.charAt(i));
                }
            }
            for(Object x:list){
                System.out.print(x);
            }
            System.out.println();
        }
    }


}
